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An Ultimate Guide: Choose the Right Flexible Rubber Bellows for Pumps

Flexible rubber bellows or expansion joints are an integral part of industrial equipment that can be found in machines in nearly every industry. These flexible rubber bellows are used to prevent the rod, piston, or other moving elements from frictional damage, contamination, and/or creating a safety issue. Given the importance of the part and demands of the application, choosing the right material and design for the expansion joint bellows is critical. This selection guide offers a few guidelines to choose flexible rubber bellows to best fit your application.

flexible rubber bellows

Guidelines for Choosing Flexible Rubber Bellows

When it comes to choosing bellows or expansion joints for your machine, it is important to address their exposure to temperature, friction, chemicals, etc. Here are the steps one should consider while choosing the rubber bellows.

  • Review the surrounding environment: The bellows is covering moving parts that are surrounded by other components and may be exposed to high temperatures, oil, chemicals, or other environmental factors that will require certain types of material or part design changes. Have a list of things that could impact performance or cause failure.

  • Understand the Movement of Joints: The joint movement causes friction, heat generation, and wear and tear. The flexible rubber bellows are mounted to minimize the impact of these factors on the system. Understanding these forces will help ensure the bellows meets your needs.

  • Consider Sealing Requirements: As bellows expand and contract, they can trap air and balloon out or create a vacuum and suck down on the shaft if a closed system is created. Many times it is important to create an air exchange in the system to prevent these issues. That can be as simple as adding an air admittance tube to the assembly.

  • Consider Attachment Requirements: How do you plan on attaching the bellows on both ends? Minimizing the difference between the type and size of the ends can help control costs. Ends can be as simple as a smooth cuff or may include a custom flange tapped with holes for mounting.

  • Outside Dimension Requirements: Making sure your ideal part can fit inside your footprint is something that is often overlooked, especially with high expansion ratio requirements. The greater the difference between the minimum and maximum length, the larger the OD of the bellows.

In addition to following the above-mentioned guidelines, you should source your flexible rubber bellows, sleeves, and boots from a reliable manufacturer like Crushproof Tubing. The company offers high-quality expansion joints, and rubber sleeves, and boots for almost any application.

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